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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Aeronautical & Space Sciences
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Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 39, Issue 12 - Dec 2011
Volume 39, Issue 11 - Nov 2011
Volume 39, Issue 10 - Oct 2011
Volume 39, Issue 9 - Sep 2011
Volume 39, Issue 8 - Aug 2011
Volume 39, Issue 7 - Jul 2011
Volume 39, Issue 6 - Jun 2011
Volume 39, Issue 5 - May 2011
Volume 39, Issue 4 - Apr 2011
Volume 39, Issue 3 - Mar 2011
Volume 39, Issue 2 - Feb 2011
Volume 39, Issue 1 - Jan 2011
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The Extension and Validation of OpenFOAM Algorithm for Rotor Inflow Analysis using Actuator Disk Model
Kim, Tae-Woo ; Oh, Se-Jong ; Yee, Kwan-Jung ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1087~1096
DOI : 10.5139/JKSAS.2011.39.12.1087
The purpose of current study is to develop and verify the newly developed solver for analyzing rotor flow using the open-source code. The algorithm of standard solver, OpenFOAM, is improved to analyze the rotor inflow with and without fuselage. For the calculation of the rotor thrust, the virtual blade method based on the blade element method is employed. The inflow velocities on the rotor disk used to specify the effective angle of attack, have been included in the solver. The results of the current rotor inflow analysis are verified by comparing with other experimental and numerical results. It was confirmed that the modified solver provides satisfactory results for rotor-fuselage interaction problem.
Aerodynamic Simulation of Air-Launched Missiles from a Complete Helicopter
Lee, Hee-Dong ; Kwon, Oh-Joon ; Lee, Bum-Seok ; Noh, Kyung-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1097~1106
DOI : 10.5139/JKSAS.2011.39.12.1097
Unsteady numerical analysis was performed to simulate air-launched missiles from a complete helicopter in hover by using an unstructured overset mesh flow solver coupled with a module of six degree-of-freedom motion of equations. The unsteady computations have been performed to obtain flow fields around the complete helicopter including main rotor, tail rotor, and fuselage equipped with multiple missiles, and six-DOF simulation has been performed to predict the behavior of the air-launched missile. The effects of the launching position and the missile thrust on the trajectory of the missile were investigated as well as the aerodynamic interference of the air-launched missile under the unsteady downwash produced by main rotor.
Fatigue Life Prediction of a Laser Peened Structure Considering Model Uncertainty
Im, Jong-Bin ; Park, Jung-Sun ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1107~1114
DOI : 10.5139/JKSAS.2011.39.12.1107
In this paper, the fatigue life of a laser peened structure was predicted. In order to calculate residual stress induced by laser peening finite element simulation was carried out. Modified Goodman equation was used to consider the effect of compressive residual stress induced by laser peening in fatigue analysis. In addition, additive adjustment factor approach was applied to consider S-N curve model uncertainty. Consequently, the reliable bounds of the predicted fatigue life of the laser peened structure was determined.
An Image Processing Algorithm for Detection and Tracking of Aerial Vehicles in Short-Range
Cho, Sung-Wook ; Huh, Sung-Sik ; Shim, Hyun-Chul ; Choi, Hyoung-Sik ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1115~1123
DOI : 10.5139/JKSAS.2011.39.12.1115
This paper proposes an image processing algorithms for detection and tracking of aerial vehicles in short-range. Proposed algorithm detects moving objects by using image homography calculated from consecutive video frames and determines whether the detected objects are approaching aerial vehicles by the Probabilistic Multi-Hypothesis Tracking method(PMHT). This algorithm can perform better than simple color-based detection methods since it can detect moving objects under complex background such as the ground seen during low altitude flight and consider the characteristics of vehicle dynamics. Furthermore, it is effective for the flight test due to the reduction of thresholding sensitivity against external factors. The performance of proposed algorithm is verified by applying to the onboard video obtained by flight test.
Smooth Path Generation using Hexagonal Cell Representation
Jung, Dong-Won ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1124~1132
DOI : 10.5139/JKSAS.2011.39.12.1124
This paper deals with smooth path generation using B-spline for fixed-wing unmanned aerial vehicles manuevering in 2D environment. Hexagonal cell representation is employed to model the 2D environment, which features increased connectivity among cells over square cell representation. Subsequently, hexagonal cell representation enables smoother path generation based on a discrete sequence of path from the path planner. In addition, we present an on-line path smoothing algorithm incorporating B-spline path templates. The path templates are computed off-line by taking into account all possible path sequences within finite horizon. During on-line implementation, the B-spline curves from the templates are stitched together repeatedly to come up with a reference trajectory for UAVs. This method is an effective way of generating smooth path with reduced on-line computation requirement, hence it can be implemented on a small low-cost autopilot that has limited computational resources.
Design Space Exploration of the Hall Effect Thruster for Conceptual Design
Kwon, Ky-Beom ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1133~1140
DOI : 10.5139/JKSAS.2011.39.12.1133
Current design process for the Hall effect thruster has relied on expensive experimental method based on the limited historical data. In this study, a proper design space for the Hall effect thruster is chosen and associated design space exploration is conducted based on a recently proposed numerical method in order to improve current design process. According to the results of the design space exploration, performance envelope is determined for the given design space and the correlations between performance metrics are analyzed. Further analysis shows that main factors in performances for the Hall effect thruster are the anode mass flow rate and the discharge voltage.
Effects of Nozzle Characteristics on the Rear Fuselage Temperature Distribution
Yi, Kyung-Joo ; Baek, Seung-Wook ; Lee, Sung-Nam ; Kim, Man-Young ; Kim, Won-Cheol ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1141~1149
DOI : 10.5139/JKSAS.2011.39.12.1141
In order to enhance the aircraft survivability, infrared signatures emitted by engine parts should be diminished. For its reduction it is necessary for the rear fuselage temperature to be decreased. In this study, numerical modeling of flow fields and heat transfer of nozzle is performed and its temperature distribution along each component wall is predicted. The effects of material characteristics and shape of nozzle wall and radiation shield on the heat transfer are also investigated. Through this numerical analysis, design parameters related to the susceptibility of aircraft are examined.
A Study on Reliability Optimal Design of Satellite system(Based on MSC System's structure of KOMPSAT-2)
Kim, Heung-Seob ; Jeon, Geon-Wook ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1150~1159
DOI : 10.5139/JKSAS.2011.39.12.1150
Reliability is defined as a probability that a system will operate properly for a specified period of time under the design operating conditions without failure. Reliability-Redundancy Optimization Problem(RROP) involves selection of components with multiple choices, redundancy levels and redundancy strategy(Active or Standby) for maximizing system reliability with constraints such as cost, weight, etc. Based on the design configuration of Multi-Spectral Camera(MSC) system of KOMPSAT-2, the mathematical programming model for RROP is suggested in this study. Due to the nature of RROP, i.e. NP-hard problem, Parallel Particle Swarm Optimization(PPSO) algorithm is proposed to solve it. The result of the numerical experiment for RROP is presented as instance of recommended design configuration at some mission time.
Three-axis Spring Element Modeling of Ball Bearing Applied to EO/IR Camera and Structural Response Analysis of EO/IR Camera
Cho, Hee-Keun ; Rhee, Ju-Hun ; Lee, Jun-Ho ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1160~1165
DOI : 10.5139/JKSAS.2011.39.12.1160
This study is focused on the structural dynamic responses, i.e., vibration analysis results of the high-accuracy observation multi-axial camera, which is installed and operated for the UAV (Unmanned Aerial Vehicle) and helicopter etc. And, the authors newly suggest a modeling technology of the ball bearing applied to the camera by using three-axis spring elements. The vibration analysis results well agreed to the randum vibration test results. Also, the vibration responses characteristics of the multi-axial camera through the time history analysis of the random vibration were analyzed and evaluated. The above results can be applied to the FE-modeling of the ball bearings used for the space cameras.
Design and Output Characteristic Analysis of Electro-Mechanical Ignition Safety Device
Jang, Seung-Gyo ; Lee, Hyo-Nam ; Oh, Jong-Yun ; Oh, Seok-Jin ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1166~1173
DOI : 10.5139/JKSAS.2011.39.12.1166
Electro-Mechanical Ignition Safety Device(EMISD) for solid rocket motor is designed and manufactured. The EMISD utilizes a true rotary solenoid for arming mechanism and an electric squib(initiator) for generating ignition energy. In order to prove the ignition capability of the EMISD, 10-cc Closed Bomb Test(CBT) is performed, which measures the pressure built by high temperature and high pressure gas generated by operating EMISD. The pressure built in the free volume of 10-cc closed bomb and the opening time of the ignition gas outlet are calculated using one dimensional gas dynamic model which is composed of the ideal gas equation and mass-energy conservation equation. Comparing the test result with model prediction, it is realized that the pressure built in the free volume of closed bomb due to the firing of EMISD, has the efficiency ratio of about 34%.
Analysis of the Single Event Effect of the Science Technology Satellite-3 On-Board Computer under Proton Irradiation
Kang, Dong-Soo ; Oh, Dae-Soo ; Ko, Dae-Ho ; Baik, Jong-Chul ; Kim, Hyung-Shin ; Jhang, Kyoung-Son ;
Journal of the Korean Society for Aeronautical & Space Sciences, volume 39, issue 12, 2011, Pages 1174~1180
DOI : 10.5139/JKSAS.2011.39.12.1174
Field Programmable Gate Array(FPGA)s are replacing traditional integrated circuits for space applications due to their lower development cost as well as reconfigurability. However, they are very sensitive to single event upset (SEU) caused by space radiation environment. In order to mitigate the SEU, on-board computer of STSAT-3 employed a triple modular redundancy(TMR) and scrubbing scheme. Experimental results showed that upset threshold energy was improved from 10.6 MeV to 20.3 MeV when the TMR and the scrubbing were applied to the on-board computer. Combining the experimental results with the orbit simulation results, calculated bit-flip rate of on-board computer is 1.23 bit-flips/day assuming in the worst case of STSAT-3 orbit.